Hyperammonemic Encephalopathy Due to Carbonic Anhydrase Va Deficiency, also known as ca-va deficiency, is related to carbonic anhydrase va deficiency, hyperammonemia due to and carbonic anhydrase va deficiency, and has symptoms including lethargy An important gene associated with Hyperammonemic Encephalopathy Due to Carbonic Anhydrase Va Deficiency is CA5A (Carbonic Anhydrase 5A).